PD17202AGF-011_15 Datasheet, PDF (10/30 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER WITH LCD CONTROLLER/DRIVER AND KEY SCAN CIRCUIT FOR FPC (FRONT PANEL CONTROLLER)

µPD17202AGF-011
3. KEY SCAN
3.1 Key Scan Function
Key scanning is started when a key data output command is executed.
The INT pin (pin 35) goes high when key scanning has ended.
The INT pin goes low when the LOAD pin (pin 28) goes high.
Figure 3-1. Timing Chart of Key Scanning
50 - 60 µs
KS0
KS1
KS2
KS3
KS4
1.6 - 1.9 ms
(2.8 - 3.4 ms)^Note
INT
Key data output
command
Scanning ends
LOAD pin rises
Key data output
command
Note The value in brackets ( ) is when “display data input + key data output” is executed.
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